A 60-day supplement combining hibiscus and lemon verbena polyphenols increased the appetite-suppressing hormone GLP-1 and decreased the hunger hormone ghrelin in overweight adults.
GLP-1 increased, ghrelin decreasedThe hibiscus-lemon verbena polyphenol supplement modulated the same appetite hormones targeted by blockbuster weight-loss drugs — boosting the satiety signal (GLP-1) while suppressing the hunger signal (ghrelin).
What the researchers found
In a 60-day double-blind, placebo-controlled trial of 54 overweight subjects, a polyphenol supplement combining hibiscus and lemon verbena extracts increased the appetite-suppressing hormone GLP-1 (glucagon-like peptide-1) and decreased the hunger-promoting hormone ghrelin. Participants also showed improvements in body measurements, reduced blood pressure and heart rate, and reported a more positive overall health perception. The authors propose that these effects may be mediated through AMPK (AMP-activated protein kinase) activation, which influences energy metabolism and fat management.
Why it matters
GLP-1 is the same hormone targeted by blockbuster weight-loss drugs like semaglutide and tirzepatide. The finding that plant polyphenols can naturally increase GLP-1 levels is significant because it suggests a dietary approach to modulating the same appetite pathway that these drugs exploit pharmacologically. If plant-derived polyphenols can meaningfully boost endogenous GLP-1 production, this could complement or provide a more accessible alternative to expensive injectable medications for appetite management.
The numbers in context
n=54 · 60 days · Double-blind, placebo-controlled · GLP-1 increased · Ghrelin decreased · Blood pressure and heart rate decreased
How the study worked
Fifty-four overweight subjects were randomized to receive either a polyphenol supplement (combining Lippia citriodora/lemon verbena and Hibiscus sabdariffa extracts) or placebo for 60 days. Anthropometric measurements (body weight, skinfold thickness, circumferences) and blood pressure were recorded at baseline, 30, and 60 days. Hunger and satiety were tracked using a validated Visual Analogue Scale at five timepoints. Health status was assessed via the SF-36 questionnaire. Fasting blood samples were analyzed for appetite-related hormones including GLP-1 and ghrelin.
Who was studied
54 overweight adults in a randomized, double-blind, placebo-controlled trial
What this study cannot tell us
The sample size of 54 is modest for a weight management trial. The 60-day duration is relatively short and doesn't address long-term weight maintenance. Specific effect sizes and statistical significance values for individual outcomes are not provided in the abstract. The postulated AMPK mechanism is speculative and not directly measured in this study. The authors acknowledge further research is needed. Industry involvement is possible given the use of a proprietary supplement formulation.
How to read the evidence
This is a randomized, double-blind, placebo-controlled trial — the gold standard design. However, the modest sample size (54 participants), relatively short duration (60 days), and lack of specific effect sizes in the abstract limit the strength of conclusions. The study provides encouraging but preliminary evidence.
When this study was published
Published in 2018, this study predates the massive public interest in GLP-1 biology driven by semaglutide's popularity. The findings are now more relevant than ever given the focus on GLP-1 modulation for weight management, and may warrant larger follow-up studies.
The bigger picture
The intersection of plant polyphenols and GLP-1 biology is a growing research frontier. As the world spends billions on injectable GLP-1 drugs for weight loss, the possibility that dietary compounds can naturally boost GLP-1 production is commercially and clinically compelling. While the effects of polyphenols are likely much more modest than pharmaceutical GLP-1 agonists, they could serve as accessible, low-cost complements to lifestyle interventions for the vast majority of overweight individuals who won't access prescription medications.
Questions still open
- How does the magnitude of GLP-1 increase from polyphenol supplementation compare to the pharmacological levels achieved by GLP-1 receptor agonist drugs?
- Would longer-term supplementation produce clinically meaningful weight loss, or do the effects plateau over time?
- Which specific polyphenol compounds in hibiscus and lemon verbena are responsible for modulating GLP-1 and ghrelin, and through what mechanism?
Common questions
Can drinking hibiscus tea boost GLP-1 like weight-loss drugs?
Is this supplement a replacement for weight-loss medications?
Read the original research
Hibiscus and lemon verbena polyphenols modulate appetite-related biomarkers in overweight subjects: a randomized controlled trial.
Food & function, 9(6), 3173-3184
Citation
Boix-Castejón, Marina; Herranz-López, María; Pérez Gago, Alberto; Olivares-Vicente, Mariló; Caturla, Nuria; Roche, Enrique; Micol, Vicente. (2018). Hibiscus and lemon verbena polyphenols modulate appetite-related biomarkers in overweight subjects: a randomized controlled trial.. Food & function, 9(6), 3173-3184. https://doi.org/10.1039/c8fo00367j